Switch machine



w. K. HOWE SWITCH MACHINE -lVlarch 3, 1931.

Filed June 14, 1929 lNV yJTOR X I TTORNEY Patented Mar. 3, 1931 WINTHBOP HOWE, or ROCHESTER, NEW YO SIGNAL COMPANY, or nooIiE'srn ',,nEw YORK swrrorr Meet-{ nn Application filed June 14, 1929," Serial No. 370,906; g

This invention relates to traffic controlling devices of'railways, and more particularly to the apparatus and circuits for operating a distant track switch irom -a local tower. 1

-In the provision of meansfor voperating track switches of railway systems, it ishigh-- ly important to employ apparatus and C11; cults for controlling the same, which areipro-z tected against operation of such track switches by the application of current from some forei n or unauthorized source, by reason of crosses, grounds, .or the like.

- In accordance with the present invention it is proposed to operateta dlstant track switch by a switch. machine of the electric motor type, and to. guard against operation'of such,

switch machine by unauthorized current 1 by the "employment; of 1 an: electro-niagnetic brake which will prevent operation. of the motor so long as the moto'rtorque is below a predetermined va'lue,thi's electro-magnetic brake being so connected in the systemthat the application. of current to both the normal and the, reverse wire will 'maintainthe,

brake applied irrespective oi' the 'ainount'of current flowing through the motor, this bein g decidedly important in the ev'ent there'is a cross between thenormal and the reverse wire in that such cross otherwise might causeunauthorized operation of the motor.

Other objects of the present invention rc-' side in the provision of meansfor permitting reversal of the switch machinewhen stalled.

in midstroke,the provision of means for prerl venting operation of the switch machine una der certain traffic conditions but to permit such operation in the event such trafic conditions exist after the switch machine operation" has been initiated. Z I j ()ther objects, purposes, and characteristic features of the invention will in part be obvious from the accompanying drawingand in part be described hereinafter;

- In describing the invention in detail referencewill be made to the accompanying drawing, inwhich the dotted rectangle represents a towerhousing the apparatus at the local point, and the remaining apparatus is that located at a distantltrackway location,

AssIGNoa 'ro GENERAL nA rwar -;Referring to the drawing, the main track has been represented bytrack rails 1, which are connected to thetrackrails 2 of a pass: l I ing siding, through the medium of a track switch S, this track switch S beingoperated by switch-machine SM; The track switch 13 has associated therewiththe usual detector trackcircuit includi-ngz'the track relay TR, and the track battery4. Similarly, there is v an approach track section havin a track circuit ncludinga track :relay T 1 and a includes a reversible-motor of the double field winding type, includingan armature 5, a

normal "field winding 6 for operatingv the switch machine in a direction to place the track switch S inits main track position, and a reversingfield windlng 7 This motor has associated therewithabrake drum 8 adapted V to be'engaged by the brake shoe 9.- This brake shoe 9 .is' urged against the brake drum f8 by a compression spring 10,, an electromagnet -,track battery 3.t :This switch machine SM comprising windings. l6 and 17 i being employe'd to .releaselthe spring operated brake 8-;9. Attentionisdirected to-the fact that r these windings 16 and 17 are connected in series with field windings'6 and 7, respective- 'ly, and that the brake windings 16 and 17 are wound inopposite directions withrespect to current flow from left to right in their-circuits, This arrangement of the windings 1G and 17 is an important feature of the electromagnetic brake, in that should a cross occur between the normal'and, reverse wiresyN and R, to permit flow of current in both the windings 16 and 17, their efliects would be new tralized and the brake 8'9 would not hereleased. I I Y r In the local tower T is provided the usual switch machine control-lever 19, which'mayf vor may not be interlocked with other levers dependlng upon the type'of system of which the switch machine SM forms a part. This lever 19 thro-ughthe medium of movable contacts 20 and 21, a'dapted-to-engage stationary contacts 22, 23, 24', and 25 may'control the distant switch machine Associated with this lever 19 is a protection relay PR, having ahighresistance,winding'H and a low resistance winding L11 Itis believed that the structure of the system and its operating features will behest understood by considering the operation of the system. i

I9 pe1'at2'0n.Attentionis directed to the fact that the track switch S is now in its normal position, as is also the switch machine SM controlling the same, and similarly, the

lever 19 is in its normal position. Let'usas tact ottherelay TR, wire 33,1iigh. resistancewvinding H of the relay PR, wire 34, low resistance winding L of the relay PR, wires 35 and 36, contacts 23, reverse wire R, contacts 37-3 8,"wire. 89, winding'l'i of the electro magnetic brake 8-9,.field winding 7, armature 5, common returnwire C, wire-l0, tuse ll, hack to the negative. terminal of the 7 Battery The circuit just traced will not effect operation of the switch machine, because the resistance of thefwinding H is .so high that very little current flowszin this circuit. The flow of current in the circuit just traced, will however eiie'ct energiZat-ion oi the protective relay thereby eiiecting closureof its con-v mania, and opening ii its 'coiita'ct 48. Closure of the contact 42 shunts the high resistance winding H and the increase .of current ilow in the circuit is sutficient to release the electro-magnetic brake 8-9 and operate the switch mach-inc motor, this increased current fimvin'g in the circuit being suiii'cient to maintain. the contactetQ oi-therelay PR: closed by reason otthe currentflow in the low resistsince ri s. winding L of this relay PR.

A. r few revolutions of operation of the motorfl)-7 thecontactsl7%8 or the switch machine SM are closedythis construction is resorter to in order to permit reversal o t-the switch machine in midstrolre if this should be required. Attention is directed to the fact that there is no flow of current through either the hold winding 6 or the electro-magnetic brake winding l6,because the contact 43 oi the relayPRisnow open and prevents flow of cur rent through those windings. switch 11G machine motor 5? will thus continue to operate until it has moved the switch S to the take-siding position, at which time the con ta'cts 37-'38fopen and cut'oti the flow of ourrentfto the motor 5+7. It thus appears that the contacts 38 are contacts'o'f the makelietore-break type, in that both contacts 3T-38 and at? are closed at substantially all "timesexcept when the SWltCliillilChiRQ assumes an extreme position, this feature per- I netic brake Sj 9 aiiords locking whichinsome cases maybe deemed adequate.

In substantially the same way as just explaine'd'r'eturn otthe lever 19 to the normal position will close the following circuit for energizing the relay PR- and then returning the switch machine SM to its normal position':-beginning at the positive terminal of the batteryB, fuse 24, wires 28 and 29, con

tact 30, -wire 3l,contact 32, wire 33, winding nor therelay PR, wire 3%, winding L of the relay PR, wires andL50, contacts 20'22, wires 51 and l. contacts iT- 8,wire 52,winding 16 of the el ctro-magnetic brake 8-9, field winding 6, armature 5, common return wire C, wire. l0, fuse/41, back to the battery B.

The completion of this circuit eliects energiz-i ation of the relay PR thereby closing contact.

42 of this :relay PR to allow sufliclent current to flow in the circuit to operate the switch machine SM back to its normal position, at which point in the operation the conta'cts 47 -48 are opened. It should be noted that in'the event there is atrain moving in the normal direction of 'trafiic from left to right, as indicated by the arrow, its treading upon the traclrcirc'uit will deen'ergize the track relay T-R lout this de-energization of I relay TR will not stop operation "of the switch machine-at some intermediate point inits stroke,.-bec'ausethe contact 42 of the protection relay-PR1 has already shunted the winding H,- this relay including in series thercwitlrthe contactfiO of the relay T11 so that theswitch machine SM will continue its operation and complete its stroke before the trainv in question reaches the switclrS. The track circuits containing track relays TR and TR extend back a suthc'ient distance to preventatrain moving at its maximum speed reaching the track switch-S- betore the switch machine SM has completed its stroke.

Letus now assume that the apparatus assumesitsnormal condition, as shown in the drawings, and that current is applied to the of the protective relay PR, wire 40, fuse ll,

to the negative terminal of the battery B,

and this flow'of'cur rent would presumably be of such; high value that it would cause the fuse 41 to blow, thereby calling attention to the fact that there is something wrong which would be corrected by the maintainer.

The application of current toth'ereverse wire R, as just explained, would also permit a small QIHOUDtOfCllII'QIlt to flow throu h the switch machine motor 5'Z,-but this ow of current would be toosmall to cause operation of the switch machine SM by reason-of the low resistanceof the partial circuit just traced and'in'multiple therewith, and also the. fuse 41' would probably blow-very quicklyso that the switch machine 5--7 would not be operatedn a v; c

Let us nowassume-thata cross occurs between the wires N and'R; with such a cross between wiresN and R the following circuit through the switch machine SM would be to battery B is completed, but this-branchcir cuit is onlyclosedmomentarily-because the relay PR picks upiminediatelyi' upon closure of. the circuit. through"; the switch: machine motor. The closure ofrthisci'rcuit willwenergize the protective relay for:reasons heretofore given thereby completinga circuitof comparatively low resistancefor the switch machine motor 5,-.7. Theiflowof currentin this low resistance i..circ.uit ..,will allow the switch machine tooperate a revolution or two, after which the contactsA'L-QS of the make-before-break to-divide betweeniwindings 16 and 17 of the electro magnetic brake ,8.-9. Since these windingslG and 17 'buclreacli other, that'is are wound in opposite'directions, the electro-magneti'c: brake 8-9 will be applied, thereby-preventing further operation of the switch machineSM. In this connection, at-! tention is also directed to the fact that with thercurrentdivided, as just explained, the

field windings 6 and 71 will substantially neutralize each other'so thatthe' flow of current in the armature 5 will produce 'very' little torque, if any.

- A control circuit for a switch machine has thus; been provided, invxw-hich the lever 19 may be a two-position lever, and in which the false operation of the switch machine is guarded against by being protected by shuntingcircuits including theback contact 43 of thefiprotective relay PR in the event that unauthorized current is applied to either the contacts 37-38 and: LT- &8 will close, thereby causing thecurrent the protective relay PR prevents operation of the-switch machineSM'in the'even't there is a'train approachingin the approach section. at th'e time that the'lev'er' is operated,

The protective relay PR als0 permits the switch machine to complete itsxstroke inthe normal'or the reverse wire; and in which event there, is a train enteringtheapproach section after operation of the switch machine has been initiated. "The apparatus of the present-invent on also includes an electro-- magnetic brake containing windings which neutralize each other in the event current is applied to both of them at the same time,

this arrangement preventing false operation of the switch machine in the event a cross occurred between the normal and reverse wires Nand R. j j

' Having thus shown and described one spe-" I cificembodiment ofthe present inventibnfit isdesired to be understood that the particular embodiment illustrated has been selected a for the {purpose of facilitating descriptions of its structure as well as its features of operation, more than with the intent of showing the exact construction preferably-em ployed in practicing the-same 'or the scope bf theinventiom'and that various changes, *modifications, and additions maybe/made to adapt the invention to the particular railwaysystem or interlocking plant in connection with which the invention is to be used,

all without departing from theispiritor scope ofthe invention orthe ideaof means underlying thesame,;except as demandedby the scope'of thefollowingclaims. f

, What I claim as new is llQCAswitch macliinefor operating distant track. switches comprising, a. throw. rod,--a I reversible motor for operating said throw rodincluding an} armature and two field windings so connected that: if current is 7 caused to flow through saidarmature and one of said field windings said armature will bevoperate'd in one direction and if current is caused'to flow throughsaiid armature and said other field winding said armature is caused tooperate in the other direction, and

a spring actuated electro-magnetieally released'brake havingtwo windings, one connected in series with one of saidfield winch r in-gs and the other connecte-din seriesfwith the other field winding, the turns of the brake windings being so arranged that if both of said field windings are energized s1- inultaneously said brake will not be released.

l-i l 2. A switch machine for operatingdistant track switches comprising, a throw rod, a

reversible motor for operating saidthrow rod including an] armature and two field windings so connected that if current is 1 caused tofiow through said armature and '7 one of said field windings saidarmaturewill' be operated in one direction and 1f current is caused to flow through saidarmature and said other field winding said armature is caused-to operate in the other direction, and a :spring actuated electro magnetically released brakehaving two windings, ojne connected in series with one of said field windings and the other connected in series-with the other field winding, said brake windings having their turns so arranged and of such number that said brake will not be released it said armature is energizedby current fiow-.

ingfthrough said field windings in multiple. Cross-protection ineans for preventing operation of a switch machine for operating track switches in response to a cross-betweenthe usual normal and reverse wire 1n switch spring means for normally holding said' brake applied, andelectromagnetic means effective to release said brake if said motor is energized oil of either said normal or said reverse wire-:but in'efiecti-ve torelea'se said brake if saidl m-otor isenergized by 'receiving current from both the normal and the reverse wire simultaneously; f 7' In a switch machine *control circuit, thecombination with a switch machine constructed to operate in one direction ifpoten tial is appliedacross'its normal terminal and common wire; and to operate in the reverse direction: ifpotential' is applied acrossflits reverse terminal: and. a common wire; and a normally active electro-magnetic brake, re-" leased automatically if said switch machine is energized in either of the waysabove 8])001 fied but not released if said normal and re verse wires are'connected together and po-, tential' is applied between them and the common wire.- H a 6. A switch machine for operating railway switches and a, control circuit therefor comprising, apparatus including a reversible .rn'otor'and two sets of contacts the normal set of which is-open when the switch machine assumes the no 'mal position, the reverse .set of which is open when the switch machine assumes the reverse positionand both sets of which are closed when the switch machine assumes an intermediate position; a normally de-energ ze'd andnormally active elcc troanagne'tic'brake for said motor having two brakewlndings either of which if energized will 'ren'dersaid brake inactive; a normal tion; by foreign current.

circuit for said motoriincluding a :normal wire, said normal set of contacts and one of said brakelwindings in series; a reverse circuitforsaid motor including a reverse Wire, said reverse set .of jconta'cts and the other brake; winding; inseries; said one andsaid other brake winding being so connected-in their respective circuits that their fluxes will neutralize and said brake will be active if both of. said circuits are closed simultaneously.

in combination, a switch machine operable in one direction over a normal circuit including a normal wire and a common wire and operable in-the other direction over a reverse wire and said common wire, a lever for closing either said normal or said reverse circuit through a current source having one terminal connected to said common wire permanently,a protectiverelay havingta high resistance and a low resistance winding con nectcd-inseries and in series with said source and'having front contact for shunting said high resistance winding, and a baclr contact on said relay connecting the. then disconnected normal or reverse wire to'said common Wire, whereby said loackcontact provides a shunt for said switch machine'toprevent its opera J8. A switchmachine comprising; a motor of. the double field typewherein the two field windings'are connected together and their unction is connected to the armature, the

turns insaidfield windings being so arranged that :izi one terminal of a source is connected to the, free b rush: of said armature and the other terminal'of said'source is connectedrto one'free field causes operation of said motor inone direction, and if connected-to the other free field terminal causes operation of said motor-"in the other direction; anda de-energized normally inactive electro-magnetic brake for saidmotor having two windings, one connected in series with one field Iwinding and the other connected series with the other field winding, with the turns so a-r- T verse direction if potential is applied across its reverse terminal and a common wire; and a normallyactive electro-magnetic brake, released automatically if said switch machine is energized in either of the ways above specifiedbut not released if said normal and reverse wires are connected. together and po tential is applied 'between'them and the commonwire, a track relay, and means for preventing operation of said switch machine if such operation is initiated aftersaid track relay is de-energized hut permitting continuation of its operation until it has completed its operatingstroke if said track relay is dez-energized while said switch machine is op- I crating. I c v 10. In combination, a motor for operating the switch points of atraok switch, asprin'g actuated brake for preventing rotation of said motor, a normal wire and a reverse wire 'for operating said motor in the normaland reverse direction respect1vely,- two d1fierentially wound coils for releasing said brake one coil of which is included in the normal wire and the other of which is included in v the reverse Wire, whereby if the normal and the reverse wires are simultaneously connected to a source of current said brake is not released but is released if either thenormal or the reverse Wire are so connected.

In testimony whereof I afiix my signature.

WINTHROP K. HOWE. 

